Recently, the international demand and production of biodiesel oil (biological diesel oil) are increasing rapidly and the main by-product thereof such as glycerol is also produced abundantly. The key to support the sustainable development for biodiesel oil and the critical task to produce biomass chemicals lie in: researching and developing the bio-based glycerol with an enormous development potential, finding new approaches to produce new products with high additional value from the by-product of biodiesel oil such as glycerol, reducing the cost of biodiesel oil, prolonging the industry chain of biodiesel oil, and increasing the market competitive power of biodiesel oil.
The downstream products of glycerol are various and have attracted the people's universal attention, such as 1,2-propylene glycol prepared from the hydrogenation of glycerol. 1,2-propylene glycol is an important non-toxic chemical primary material applied widely and the main use thereof is being the intermediates of coatings and reinforced plastics during the production of unsaturated polyester resins. 1,2-propylene glycol is the primary material for unsaturated polyester, plasticizer, surfactant, emulsifier and demulsifier. In the industry of polyesters, 1,2-propylene glycol is used for the primary material of polyester polyols, the initiating agent of polyether polyols, the chain extension agent of polyurethane and the like. 1,2-propylene glycol can also be used for antifreezing agent and refrigerant; it has superior sterilizing property and wettability. It can be wildly used for the industries of perfume material, food, cosmetic, medicine, baccy and the like.
There are already many research subjects in China and abroad being carried out and developed on how to realize the preparation of 1,2-propylene glycol from the hydrogenation of glycerol using new process and new technology. Davy Process Technology Co. (WO2007/010299 A1) realized a glycerol conversion of 97˜100% and selectivity for 1,2-propylene glycol of 93˜97% by using a copper-based catalyst produced by itself.
Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (Chinese Patent Application No. 200610105255.X) reported a method for preparation of 1,2-propylene glycol from the hydrogenation of glycerol, wherein, a mixed solution system composed of 47.4% of glycerol, 14.3% of water and 40.7% of ethanol was reacted using CuO—SiO2 catalyst under 190° C. and a pressure of 8.0 MPa. The glycerol conversion was up to 96.3% and the selectivity for 1,2-propylene glycol was 99.1% or more. However, this reaction system has the disadvantages of too high reaction pressure and low catalyst stability.